Method for applying coating chemicals to yankee dryers for tissue and towel production
A method applying a composition to a dryer cylinder is provided. The method includes determining an amount of water to apply onto a surface of a dryer cylinder based on a total evaporation rate of the dryer cylinder and spraying a composition including the water and a coating chemistry onto the surface of the dryer cylinder. Systems for applying composition to dryer cylinders are also provided herein.
1 . A method of applying a composition to a dryer cylinder, comprising:
determining an amount of water to apply onto a surface of a dryer cylinder based on a total evaporation rate of the dryer cylinder; and
spraying a composition comprising the water and a coating chemistry onto at least a portion of the surface of the dryer cylinder.
2 . The method of claim 1 , further comprising adjusting the amount of the water sprayed to the surface of the dryer cylinder by adjusting a water pressure.
3 . The method of claim 1 , further comprising adjusting the amount of the water sprayed to the surface of the dryer cylinder by adjusting a distance between the surface of the dryer cylinder and a spraying device.
4 . The method of claim 1 , further comprising determining an evaporative load of the dryer cylinder.
5 . The method of claim 4 , further comprising spraying the composition with a coating shower, wherein the evaporative load of the dryer cylinder is calculated according to formula I:
EL=SFCS/SA formula I
wherein EL is the evaporative load of the dryer cylinder given in liters per second per meter squared (L/s/m 2 ); SFCS is sprayed flow through the coating shower given in liters per second (L/s); and SA is a total surface area sprayed given in meters squared (m 2 ).
6 . The method of claim 1 , wherein the total evaporation rate is calculated according to formula II:
Rw= B*W*S *([ L/E ]−1) formula II
wherein Rw is the total evaporation rate given in grams of evaporated water per second (g/s); B is basis weight at a reel given in grams per meter squared (g/m 2 ); W is paper width given in meters (m); S is reel speed given in meters per second (m/s); L is dryness of a sheet at a hood outlet given in percent (%); and E is dryness of the sheet at a hood inlet given in percent (%).
7 . The method of claim 3 , wherein the spraying device is a spray boom.
8 . The method of claim 1 , wherein the dryer cylinder is a creping cylinder.
9 . The method of claim 1 , wherein the amount of the water applied onto the surface of the dryer cylinder by spraying the composition is about 3 liters per minute to about 20 liters per minute.
10 . The method of claim 1 , wherein the composition is sprayed onto the surface of the dryer cylinder using a spraying device operating at a pressure of about 40 psi to about 120 psi.
11 . The method of claim 1 , wherein a difference between evaporative load and the total evaporation rate is about 0 to about 150 kg/h/m 2 .
12 . The method of claim 1 , further comprising measuring dryness of a paper sheet at an outlet of the dryer cylinder.
13 . The method of claim 1 , wherein the coating chemistry comprises a creping adhesive.
14 . The method of claim 1 , further comprising spraying the composition comprising the water and the coating chemistry onto the entire surface of the dryer cylinder.